Paper



April 13, 1937.

E, c. scHAcHT PAPER Filed Oct. 27, 1932 \c COO Patented Apr. 13, 1937PATENT OFFICE aoi'tole PAPER Elmer C. Schacht, Troy, N. Y., assignor toBehrnx Corporation, Troy, N. Y., a corporation of MassachusettsApplication October 27, 1932, Serial No. 639,907

8 Claims.

The present invention relates to the method of manufacturing paper-likeor sheet material products, particularly the products of my Patents Nos.1,888,409, November 22, 1932 g 1,888,410, November .22, 1932; and1,904,087, April 18, 1933, and this application is a continuation-impartof the applications which matured into said patents.

The principal object of the invention is to produce the sheet materialsand particularly those of my aforesaid applications, that is, flexiblematerials comprising (1) a web of a mixture of separators such ascomminuted cork and bre having a rubber-like binder incorporated thereinin accordance with my earliest application and (2) a web the laminae ofwhich comprise cork or other separator and fibre and fibres respectivelyf and in which is likewise incorporated a rubberlike binder inaccordance with the second of the above-mentioned applications. Toobtain'these sheet materia1s,I have developed a method which iseilicient for large scale production and enables uniformity to beobtained in the final product.

Broadly speaking, I am particularly concerned with producing thesevarious paper-like materials bya method wherein the sheets are formed assingle ply webs, i. e., non-laminated Webs on the usual Fourdriniermachine or are built up of plies after the manner of paper makingpractice in which a cylinder paper-making machine or multipleFourdrinier machine is employed and wherein the respective stocks areformed into laminated webs and Y felted together in th machine.

Thus I will follow this invention in producing (1) single ply webs; and(2) multi-ply webs, the latter having its lamina composed of (l) amixture of separators and fibres; (2) :fibres-exclusively, and (3)certain laminae composed of fibres and separators and other laminae ofbres exclusively. I incorporate in the webs of these various structuresbinder materials in predetermined percentages, so that the respectivelaminae of the ultimate sheet will. contain:

(a)` 'I'he same percentages oi the same binder;

(b) DiiTerent percentages of the same binder;

(c) The same percentages of diierent binders; and f (d) Differentpercentages of different binders, whereby the characteristics of therespective plies can be controlled.

The binder preferably employed is rubber-like and comprises rubber or arubber composition, that is normal latex, balata or gutta percha, or arubber compound of one or more of these raw materials with or withoutsuitable vulcanizing agents, coagulants, activators and accelerators. Iiind that by coating the components-of the respective webs with arubber-like binder, that a very acceptable article can be produced.

Again, I obtain a single ply or integral stratified 5 web in which thelamination or laminations of the built-up structure are controlled as to(1) relative density, and (2) components. that is the kind and amount of(a) fibres, (b) comminuted cork or other separator and (c) binderpresent. The relative densities of the layers will be controlled by thesize of the cork particles, the type of bre used, and the length of timethat the stock is subjected to beater action and the percentage of therespective components. The structural components of one layer may becomposed solely of fibres and that of another layer of comminuted corkand bres; the layers may be formed solely of fibres and of respectivelydifierent types, or solely of a mixture of cork and fibres and ofvariable mixtures respectively. The binder employed may be the samethroughout the stratied web or each layer may have a different binderincorporated therein. The amount of binder present is regulated withrespect to concentration and also with relation to the density of theweb.

In this way, control of the coeflicients of (1) absorbency, (2)strength, and (3) resiliency, i. e., compressibility and rebound, may behad and varied at will (as well as relative flexibility and stiffness)in the ultimate product.

A very important object of the invention, therefore, is to produce sheetmaterials of the character of my aforesaid applications wherein a veryprecise control may be had of the structure of the sheet.

The method embodies paper making practice as described with either ofseveral final or intermediate steps which are each emcient toincorporate the binder. Thus I proceed (1) by a m method of saturationafter the web is formed; (2) by recourse to pre-mixing, i. e., mixingthe binderf" with the other components before the stock is beaten, or(3) by beater addition, that is adding the binder to the stock in thebeater.

In each case the control features outlined above are available, can beoperated with exactness and enable a uniform sheet to be obtained.

Sheet material according to this invention may be formed to have thefollowing alternative structures:

(a) Facing layer and bottom layer (b) Facing layers and intermediatelayers (c) Alternative layers corresponding to the re- 55 spectivefacing layers and bottom or intermediate layers.

(a) (b) (c) Wherein the facing layers are (1) Thin, equal to or of lessthickness than the bottom layer or intermediate layers, or vice versa.

Of less density than the bottom layer or intermediate layers, or viceversa.

Of the same structural components or mixtures as the bottom layer orintermediate layers or vice versa.

Of a different structural component or mixture than the bottom layer orintermediatelayers, or vice versa. Permeated with the same binder as thebottom layer or intermediate layers, or vice versa.

Permeated with a different binder than the bottom layer or intermediatelayers. Permeated with a greater amount of binder than the bottom layeror intermediate layers, or vice versa.

Permeated with a binder of greater concentration, i. e., having a higherpercentage of binder than the bottom layer or intermediate layers, orvice versa. Permeated with a binder compatible or harmonious with adesired surface coating or finish.

(d) Each of thel products of (1) to (9) inclusive provided witli (1) afacing, (2) a backing, (3) a facing and backing and (4) a core ofilexible or stiif preformed material such as paper, cardboard,vulcanized fibre, cloth or open mesh fabric, synthetic resin, orvulcanized latex or rubber, forming a flexible or stiff permeable orimpervious reinforcement.

It is an object of the present invention to produce sheet materialcapable of wide application, which may be decorated, is light in weight,soundproof. abrasion or wear resistant, inert with respect to the actionof Water or organic and inorganic solvents, and porous and absorbent orimpervious and non-absorbent.

'I'he products of the present invention are useful in the manufacture ofgasket and sealing material, rug anchors, press blankets for impressioncylinders of printing machines, floor coverings, articial leather, wallboard, panel material, breaker strip for doors and jambs, i. e., forrefrigerators, electric and heat insulating material, anti-squeakmaterial, channel material, soundproof material, lnsoles, and tabletops, as well as numerous other applications. 'I'he sheet materials arecharacterized by (1) high tensile strength, (2) resilience, i. e.,compressibility and rebound, and (3) exibility and pliability in thatthe sheets may be sharply flexed or creased without cracking or theformation of weakened areas.

I attribute the excellent qualities of these products in part to themethod employed in their manufacture. Webs of the structure describedwithout a specially incorporated material will be resilient and cellularby reason of the presence of the cork, and strengthened because of thefibres, but are subject to cracking and formation of permanent weakareas under sharp flexins.

I prefer paper making practice because the web obtained may becontrolled very exactly, and like wise the incorporation of the binderwhich is essential to the production of my sheeted articles can beprecisely regulated and accomplished. In addition to these advantages,the paper making practice enables a sheet to be obtained wherein thefibres and cork are interlaced and intimately associated in what may bedescribed as hinging or pivoting of the bres on the cork particles,thereby forming a strong and resilient web characterized by numerousvoids and interstices. In other words, from a careful examination of thesheeted articles having the binder incorporated therein and formed bythis method, it has been determined that when the cork fibre sheet isbent, cracked, or deformed, what actually occurs is that the fibres atthe point of deformation are relieved to cause the cork particles whichseparate the fibres to compress. This allows the fibres to accommodatethemselves or become aligned instead of being forced to absorb theentire strain and therefore become ruptured. The cork being highlycompressible, returns to its original shape after the strain has beenremoved, and this causes substantially all of the fibres to resume theiroriginal positions in an unbroken state. Thus the sheeted articles underabnormal strains will not retain permanent lines of cracking orbreakage.

The sheet materials are moreover cellular and absorbent, i. e., capableof exerting capillary efherent characteristics and enhance itsflexibility, ."1

strength and resistance to bending strains. By reason of the method ofthis invention, the stratified Web will have its respective layerssimultaneously produced and bonded together as by felting. In otherwords, I find that by controlling the make-up of the web and theincorporation and selection of the rubber-like binder, that the normalcharacteristics of the web are improved and such weaknesses as lack ofresistance to bending strains and tearing strains are effectivelycorrected.

It is an aim of the invention to produce a web or sheet adaptable forfloor coverings or other applications Where a wear resistant surface isrequired. In such a case the facing layer will be provided with arubber-like binder having (1)l a very strong bonding coeilicient, (2)abrasion resistant and resistant to the effect of water, solvent orchemical action and (3) present in large enough amount to insure thedesired result. The f bottom or intermediate layer may have any sultabletype of binder or the same binder,I but the binder will be presentpreferably in much less amount in the nexposed portion of the web.

Thus a floor covering made as a cork ibre product will have its toplayer made as a highly absorbent structure which would, in a saturatingprocess, take up a great deal of resin, rubber latex, or some glutinousadhesive so as to give the covering a high wear coefficient, and plainfibres will also in some cases be used in this top ply so as to also geta smooth surface for coating with ornamental designs with such materialas enamel, paint or lacquer. The center section will be more dense so asto be less absorbent during the saturating process and thereby save onthe cost of the saturant during the manufacturing process. The bottomlayer will be composed of coarse cork particles and fibre so as to havea good non-slip surface, as where it is used for small rugs.

Similar floor coverings would likewise be made by introducing a highpercentage of resin or rubintroduced in the intermediate r bottom`plies, thus saving on the cost of saturant, while producing a veryacceptable product that has a high wear coefficient on its surface. K IIn the manufacture of artificial leather I preferably` resort to thelaminated structure having a vcork and fibre mixture layer or layerswherein the top surface is composed exclusively of fibre and of highdensity, so as to absorb just as little of the saturant and give thehigh native paper strength. 'I'his all-fibre ply may be calendered so asto give a very nice surface for coating or embossing, and the cork fibreply gives a fine suede-like or leathery surface, after saturation l5with a rubber-like binder. This product will be pliable like leather,will have a smooth surface for receiving a finishing coating, will havea leathery appearance on the exposed side, and will have considerableresistance to tear because of the high 20 native tensile strength of theall-fibre ply which is enhanced during the saturating process. A veryacceptable artificial leather is made in the same manner by the use ofrubber latex or resins introduced either during the paper-making proc-25 ess by pre-mixing or beater addition or by subse quent saturation.

A further important object of the invention is to produce press blanketsfor impression cylinders in the printing industry. Thus I use a singleply 30 Web of cork and fibres as produced on the single Fourdrinier, ora built-up web obtained by using a multiple Fourdrinier or cylinderpaper-making machine and permeated with a suitable binder, i. e.,glutinous adhesive, resin, etc., in accordance 35 with this invention.With one or preferably both sides of the resilient web of appropriateexibility will be combined a backing of preformed material such aspaper, cloth, and/or vulcanized fibre, i. e., hard fibre or fish paper,if desired. 40 In the manufacture of insole material, I will produceeither a single ply web of cork and fibres, a multi-ply web of cork andfibres, or a multi-ply web of layers of cork and fibres and fibresrespectively, and having an incorporated binder such as 45 resin, latexor glutinous adhesive as herein recited. The principal requirements ofsuch material are (1) strength and ability to withstand stitching andsewing, (2) flexibility to maintain the shape of the insole in use, (3)resilience and 50 smoothness so as to be comfortable, and (4) absorbencyto take care of perspiration, and all of which I obtain with thisinvention. The surface layer, whether of cork and fibres or fibresalone, will be controlled as to density, i. e., absorbency, and may becalendered if required. Also a layer of pressure sensitive or heatsensitive Iadhesive is applied to the undersurface of the sheet or anysuitable adhesive or gummed surface will be desirable in some cases.Again, a backing or facing,

60 or both, of muslin or other open web fabric, may

be combined with the sheet and in fact thin leather, paper or cloth maybe utilized. The backing of course in such case may carry the adhesive.65 A further object of the invention is to produce sheet material foranti-slip rug anchors or bases for floor coverings. Thus a thin sheet ofcork and fibre permeated with a rubber-like binder in accordance withthis invention is highly satis- 70 factory to prevent slipping of smallrugs on highly polished iioors. the anchor may have a backing orreinforcement of cloth or paper, the cork fibre surface being presentedto the floor and by reason of the cellular or 75 porous nature of theweb, firmly grips the floor If desired. the upper surface of Patent1,888,410. For example, the web will have a facing layer composedsolely' of beaten fibres and a bottom or intermediate layer of cork andfibre mixture. With such a facing layer there results a product which isparticularly useful in receiving finishing coatings on the fibre facing.I havediscovered that thesaturation or permeation of a laminated productof this type affords a means of producing a very improved coated sheetmaterial. Some saturants, such as rubber, interfere with the applicationof certain finishing coatings. However, the fibre facing layer whenapplied to the cork fibre may be readily regulated in characteristicswhich affect the condition of its surface intended to receive afinishing coating. For example, it may be regulated as to density, as byselection of proper fibres or control of the period of working the massin the beater. 'I'hispermits the permeatlon thereof by the binder tosurface.v I'believ'e this may be due to thefconrA `pressibility .andkporosity of the web forming a multiplicity of vacuum cups or 4to thefrictionaly be reduced to a minimum or otherwise regulated bycontrolling the density of the fibre layer. Again the condition of thesurface of the fibre facing layer, as well as the condition of its body,may be varied as desired in any other respects independently of the corkfibre layer, since its mass is prepared and may even receive its binder,in whole or in part, separately from the cork fibre layer, as described.The combination, therefore, of the paper iibre layer with the cork fibrelayer in a product saturated with a binder, enables me to produce asurface which may receive a finish unimpaired in character by thesaturant or binder, regardless of the nature of the finish or of thesaturant. For example, if the finish to be applied is one which does notcoact well with the binder, the fibre facing may be made very dense, sothat it has a very small amount of the rubberlike saturant therein, ormay be separately impregnated, e. g., in the beater or by pre-mixingwith a binder harmonious with the finishing material, as well as withthe binder of the cork fibre layer. On the other hand, if the finish tobe applied is one which is iinproved by or is compatible with thebinder, a fibre facing less dense than in the former instance may beutilized and having a proportionately increased amount of saturanttherein. In any event, a fibre facing denser than the cork fibre layeris usually preferred.

The above and additional objects and advantages will appear as thedescription of the invention proceeds.

Figure 1 is a view showing a single ply web of cork and fibre.

Figure 2 is a view showing a built-up web, one

layer of which is formed of fibres and the other accordance with any ofthe forms of Figures 1 Figure 6 is a similar view of a laminated web lhaving a core of the preformed material.

Cil

Figure 7 is a diagrammatic view of a papermaking machine.

Figure 8 is a diagrammatic view showing the method followed for animmersion treatment and also the type of curing chamber employed withany of the several methods.

In referring to paper-making machines, it will be understood that whileI have represented for purposes of illustration in the drawing acylinder type of machine, a multiple Fourdrinier may be used with equalfacility, and I use a regular or single Fourdrinier machine where singleply webs are being produced.

The vats for the stock are indicated at I0, Il and I2, and feed therespective cylinders, the web being felted together and built-up asunderstood in the art. In other respects, the various parts of theapparatus have been lettered to describe theirfunction.

With reference to Figure 8, it will be noted that a bath is used inwhich the rubber-like or other binder is disposed and through which theweb is entrained.

The present invention is not restricted to immersion or impregnationsince I have found it equally satisfactory to incorporate the binder bypre-mixing or beater addition as above described. In Figure 8 also Ihave illustrated a curing and drying chamber wherein instead offestooning the web, which I also do in some cases, it is passed betweenrolls which may be hot or cold as desired, and this procedure is adoptedwhere the web as completed on the machine contains the incorporatedbinder. Of course, in some cases `I may incorporate the binder bypremixing or beater addition, and thereafter give the web a saturatingtreatment, from whence it may be carried over drying racks or dryingrollers, as desired. The curing or vulcanizing chamber, of course, maytake various forms, depending upon the particular binder utilized, andits temperature will be suitably-controlled to effect a setting of thebinder.

As a further condition of the method of operation, the speed of travelof the web through the drying and curing station can be controlled, andlikewise in the case of the saturating treatment, the web may be woundonto rolls and thereafter, at any suitable time, passed through thebath. or the web may be formed and continuously fed through thesaturating apparatus.

Withrespect to the vats I0, II and I2, there may be any number of these.and I have simply shown four by way of illustration. The vats Il and I2will contain the stock for the surface layers, while the vats I0 willfeed the cylinders to produce the intermediate layers or plies. Thus Imay control the stratified or laminated structure of the web bydisposing in the various cylinder vats such wet stocks with or Withoutincorporated binder as will produce the desired web.

It will be understood that by wet stocks" I mean a mixture of fibres orpulp or fibres and cork in water. All such paper-making components arethoroughly mixed with water and put in suspension before being made intoa felted sheet.

For example, the vats III may contain va. stockcomposed of a mixture ofcork and fibres while the end vats I I and I2 will contain a stock whichis exclusively fibres. Such a disposition may be reversed, and also eachof the vats may contain a stock composed of a mixture of cork and fibresor of fibres alone to produce the stratified web and the nature of therespective stocks can be varied to accord withthe ultimate productdesired.

It will be understood that the web is built-up, i. e., simultaneouslyformed and bonded by felting to produce a substantially integralstructure, characterized by the nature of the stocks fed to therespective cylinders. As I have hereinbefore set forth, webs which arenot provided' with a binder are resilient, cellular, and strong, but inaccordance with the present invention these inherent characteristics arematerially enhanced, and more important, the web is rendered stronglyresistant to tearing strains and bending and creasing strains.

In carrying out the invention, I prepare the various stocks and feedthem to the cylinder vats. For example, I will prepare the stockconsisting of a separator, that is, comminuted cork, fibres andsufficient water, and feed such stock to the intermediate vats Iii; alsoI will prepare a stock composed substantially exclusively of paperfibres and feed the same to either of the end vats II and I2 to producea surface layer or layers.

The broader phases of the process defined in the claims appearinghereinafter, may be carried out with the use of other separators thancomminuted cork having substantially similar characteristics, forexamplecomminuted barks other -than cork, leather chips and rubberparticles.

By separators, I mean materials of low specific gravity which arecompressible and/or elastic, which preferably can be screened to a sizeand which are oi' a character which retain compressibility and size whenwet or compressed and which continue to separate the contiguous fibresand tend to cause these fibres to return to their original position whenpressure has been released.

The separator or comminuted cork should be of a size which may be termedeffective. That is to say, the cork granules to be effective should notexceed, in cross-section, the desired thickness of the finished sheet,nor should they be smaller in cross-section than the cross-sectionaldiameter of the fibres. Finer cork than this will act as a filler,thereby preventing the formation of voids and air cells. and also willbe lost to a larger extent in the paper making process; likewise smallerparticles would be ineffective in acting as separators and hinges aboutwhich the fibres can fiex. I have used successfully cork particles of agrade from 50 to 150 mesh andv 30 to 50 mesh.

'I'he fibres with which the cork particles are mixed to form the webIII, should be sufficiently long (a) to contribute tearing strength tothe finished product, (b) to mesh and hold the separating particles, i.e., the cork, and (c) to make an absorbent paper, quickly permeable tosaturating solutions. Specific examples of the fibres which I employare:

Jute Absorbentalpha cellulose Rope Wood pulp fibres Hemp Cotton SisalLinen Kraft pulp fibres Asbestos.

Long wood pulp fibres The requirements for a successful binder are thatit be capable of coating the cork particles and the fibres in suchmanner that the sheet will constitute a very strongly bonded structurein which the resilience and strength will be enhanced and the finishedweb will be substantially resistant to deformation.

l shown in Figures 1 and 3 will have the libres andl cork-in intimateinterlaced relation, producing a porous or absorbent structure capableof exerting capillary effect.

Either of the webs of Figures 1 and 3 will be permeated by a selectedbinder and most important, the density oi the single ply or the densityof the respective strata of the multi-ply web may be controlled so as toregulate the amount of 'binder present when the web is subsequently 20saturated.

In the case of the stratified article, the thickness of the respectivelayers or plies I4 may be regulated on the paper-making machine inaccordance with the product desired by varying the number of cylindersemployed, by varying the machine speed or `the type 4of felt employed,and by changing other control factors which are well known in thepaper-making art.

In Figures 2 and 4, the paper-like layer I5 is composed exclusively offibres and may be relatively thin with respect to the cork and brelayers, as shown, and controlled as to density as heretofore explainedif subsequent saturation is r to be resorted to. 'I'he layers may be ofany desired thickness and density equal to each other, or the fibrelayer of greater thickness than the cork and fibre layer or differentamounts of binder may be present in the different layers or differentamountsv of different binders may be used in the various layers, all inaccordance with the ultimate product desired. i

The nal' webs obtained, that is, the single ply web or the compositeweb, will have the characteristics above enumerated, but will tend tocrack or exhibit weakened areas if sharply flexed or creased. In otherWords, this product will have a tendency toward brittleness and will notpossess a flexibility or rigidity comparable to the saturated material.

In order to obtain the products of my aforesaid applications, i. e.,flexible material, I permeate the web by permanently and insolublyincorporating therein a rubber-like flexible binder.

'I'his binder will be selected in accordance with the intended purposeof the material.

The binder creates a stronger union between the fibres and corkparticles, increases the strength and resilience of the respective websand has the particular function or capacity of overcoming any tendencyof the web to crack or weaken under creasing or folding strains. Also,according to the specic requirements of the resultant saturated product.a rubber-like or other binder can be selected which will render theproduct substantially oilproof or waterproof or both, abrasion and wearresistant, and which will be harmonious with regard to a desired coatingor finishing material.`

The binder will uniformly coat the cork particles and impregnate thelibres throughout the cellular structure of the web and will be presentin suiiicient amount to permanently insure and preserve amaximum ofstrength, resilience and flexibility in the web.

The lbinder employed will be described as a ilexible binder but it willbe understood that variations in stiffness or rigidity in the finalproduct can be obtained by choosing a binder with the requiredcharacteristics, by varying the amount of the binder present and in somecases by varying the subsequent treatment of the binder. For example, Imay incorporate a large amount of a binder which when dried or curedthroughout each of the layers of the integral web will produce a stiffsheet. Such a sheet will have the characteristics of resilience andstrength of the more flexible article and will be resistant todeformation in that it may be cut, punched, sawed or otherwise worked.The qualities in the nal product are usually determined both by thechoice of impregnant and by the amount of binder present and it shouldbe understood that the control features of this invention include theuse of dii!- ferent binders in different layers and which are controlledas to percentage or amount present.

The binder which I will describe as a rubberlike material may compriseany natural Indiarubber-containing-latex or anyIndia-rubbercontaining-latex preserved by ammonia, formaldehyde and thelike, or any gutta-containinglatex or balata-containing-latex, singly orcombined. Likewise, I will employ compositions of one or more of theabove-mentioned latices, with suitable vulcanizing agents, accelerators,activators, antioxidants and coagulants.

It will be understood that the binder fundamentally accomplishes thepurpose of bonding the cork and fibres together and its incorporation byany of the several methods is accomplished in such a manner that aconstruction is produced in which the resilience and strength of theparticular web is enhanced and, moreover, the web is renderedsubstantially resistant to deformation.A

In order that the operation of the invention may be clear, I willdescribe several of the binders which I have found successful, but itwill be understood that there are various commercial compositions whichwill be of equal value.

I will use as the binder a water solution or dispersion of normal latexhaving a content of rubber up to substantially 20% to 25% and to whichsolution is added sodium polysulphide in the amount of substantially 5%of the rubber present and 1% to 2% of piperidine pentamethylenedithiocarbamate of the rubber present, as well as an antioxident such asNeozone L (du Pont) in amount equivalent to substantially 2% of therubber content. This composition is useful where an immersion treatmentis employed. The impregnated sheet is dried at about 135 F. andsubsequently heated to about 160 F. for about twenty minutes, tovulcanize the rubber.

Where rubber is used as the permeating medium, I may, employ vulcanizedlatex or vulcanized rubber which has been dispersed or vulcanized rubberdissolved in a suitable organic solvent. If a bath saturation process isused, the web can be saturated with rubber latex to which has been addedsodium polysulphide or colloidal sulphur and a suitable antioxidant and.the web subsequently dried at about 135 F.

A preferred solution for use as a bath saturant consists of normal latexcontaining 25% to 30% rubber, 2% colloidal sulphur (based upon rubberpresent), 1% to 2% (based upon the content) of a suitable lowtemperature accelerator such as piperidine pentamethylenedithiocarbamate, 2%

(based upon the rubber content) of a suitable' activator such ascolloidal zinc oxide, and 2% Pont).

(based upon rubber present) of Neosone L (du The sheet saturated withthis solution may be dried at F. and heated to about 160 F., to cure therubber. This solution produces a very flexible product. The flnal sheetmay have a rubber content up to substantially 65% of the finishedproduct. To increase the rigidity of the product I may resort to the useof larger percentages of colloidal sulphur and longer times of curing.

I have also used re-dispersed vulcanized rubber or prevulcanized rubbercommercially known as "Vultex which requires only a drying to cure.

Since I also utilize with the rubber-like binders, other binders, thefollowing additional examples of this component are described. In thisconnection, I may pre-mix a rubber-like binder with one stock, and oneof the resin and/or glutinous binders to be mentioned with another stockor stocks and felt the same together on the paper-making machine toproduce the built-up layer having the respective laminations eachprovided with a different binder. Again, I may. by pre-mixing or beateraddition, incorporate a binder in the web which will be a rubber-likebinder and thereafter pass the web through a bath of one of the othertypes of binders to be now referred to.

With respect to permeation and saturation with a rubber composition asherein described, the respective plies of the sheet will be controlledas to density, i. e., absorbency. As for instance, a more absorbentfurnish may be used to form the surface ply of paper on the cylindermachine. The resulting web when subjected to the rubber impregnatingbath will absorb a high percentage of rubber in the surface layer, thusfurnishing resistance to wear at the point of contact when the productis in use.

These rubber-like binders afford the result that the sheet isstrengthened, its tendency to crack or weaken is replaced by flexibilityresistant to sharp creasing and folding, and the compressibility andrebound not only are not disturbed, but are made effective to a greaterdegree.

Examples of other binders are glutinous adhesives, such as casein, hide,bone, albuminous and similar glues capable of being rendered insoluble,and which can he treated or tanned, so as to become permanently andinsolubly incorporated in the structure of the sheet.

As tanning agents, I resort to one or more of such materials asformaldehyde, paraformaldehyde, hexamethylenetetramine and sodiumbichromate. In connection with the glutinous binder and tanning agent, Iutilize plasticizersl of which Aglycerine, sulphonated castor oil,diethylene glycol, and aquaresin, are examples. Thus I employ aplasticized adhesive or binder, and I find that with such a saturant thesingle ply or laminated structures are strengthened so as to beresistant to tearing, are rendered flexible, in that they will not crackunder sharp creasing or'folding and are pliable, in that regardless ofthe degree of flexing, to which they are subjected, they will return tothe normal sheet-like condition without noticeable creases or anyindication of the lines of bending. Moreover, such saturant beingpermanently and insolubly incorporated throughout the cellular structureof the webs not only lends a resilience and pliability to the sheet, butenhances, -to a remarkable degree, the inherent compressibillty andrebound.

Further examples of satisfactory flexible bindammo ers are natural orsynthetic resins of which innumerable varieties are commerciallyavailable and which may be treated by conventional processes and withmodifying agents as understood in the art. to impart the necessaryflexibility and elastic characteristics.

Of the natural resins, I resore to kauri and copal resins, degelledlinseed and China-wood oils, as well as modified China-wood oil, and ofthe synthetic resins, I find those of the alkyd, furfural andphenol-formaldehyde types, such as bakelite, are very acceptable, aswell as polymerized isoprene and chlorinated rubber. For certain uses, asatisfactory product can be obtained by impregnation with cheap materialsuch as bituminous matter or pitches. that is bitumens winch may besecured from the natural pitch lakes or as by-products from coke ovens.

Of the flexible plasticized -adhesives above mentioned, it will beobserved that many of them, such as the glutinous and resin binders arenot only resistant to moisture, but are, moreover, inert with respect tovarious organic and inorganic solvents, of which mineral oils anddistillates are examples and the rubber-like binders herein aresimilarly inert or may be rendered so when required. I

In selecting the various saturants or binders, the particular use of thematerial is the determining factor. In gasket materials it is essentialthat the article resist the action of water and oil so that it will notdisintegrate when' used to seal joints in pipes or containers conveyingthese fluids. In the manufacture of artificial leather. as well as iioorcoverings comparable with linoleum and artificial linoleum, it isessential, in most cases, that the article be moisture resistant.

The finished web when permeated with rubber latex or natural andsynthetic resins, for example,` will produce flexible floor coveringsand artificial leather not affected by water.

In the manufacture of gasket material, a rubber-like binder is quitesatisfactory if the iinished product is to be used for water or weakalkalis or acids.

With respect to binders adapted to produce stiffness in the sheet, Iwill use resins both natural and synthetic, rubber latex containing ahigh percent of sulphur and subsequently cured by a high degree ofvulcanization, animal and vegetable glues with or without the hardeningor setting agents to produce the required stiffness.

With respect to the resinous binders above f mentioned, I will use, forexample, the flexible alkyd resins or bakelite types (that is,phenolformaldehyde types) or other kinds of suitable resins available inthe trade. It will usually be found advantageous to use'both heat andthe commonly indicated solvents for the type of resin employed in orderto secure the proper degree of uidity for ready saturation in case thebath metho'd is employed. The exact procedure will depend upon themethod of impregnation and the properties of the resin used.' In somecases, the resin will be substantially pure but in other cases modifyingagents such as polymerized linseed oil or China-wood oil may be presentor suitable drying oils alone such as polymerized vChina-wood oil may beused as saturants. Subsequent curing of the permeating oils and resinswill depend upon the nature of the specific saturant or saturants usedand the properties of the product desired. 'I'hus the permeated web maybe subjected to both heat and pressure to cure the binder orto heatalone or to heat and oxygen (air) according to whether the permeatingmedium is heat reactive, oxygen reactive or both heat and oxygenreactive. Some saturants such as air drying varnishes or resins may beair cured at ordinary temperatures, but in general. higher temperatureswith shorter curing times will be preferable. As illustrations of theabove types, I prefer bakelite which is most advantageously cured withheat and under pressure, but which may be cured by heat alone; themodified alkyd resins as for example, the alkyd resins combined withChina-Wood oil and suitable driers which are readily cured by heat andoxygen (air) and the so-called air drying varnishes with either naturalor synthetic resins, which may be air-dried at ordinary temperatures. Itwill be observed that all of these various binders are capable of beingcured or vulcanized in the sheet, by heat, pressure or both.

By reason o! the piiability and resilience of the web, particularly withan incorporated binder such as described herein, it forms an excellentbase for such plastic and flexible coatings as cellulose lacquers, oroleo resin varnishes, of whichthere are innumerable commercial varietiesavailable. Such lacquers utilize, as a base, a cellulose derivative,such as cellulose nitrate or cellulose acetate, together with a gum andplasticizer, and the present sheet material will cooperate with such acoating to prevent cracking of the coating film. I will also employChina-wood oil varnishes and linseed oil varnishes which likewiseareexible and of which a number of commercial varieties are obtainable.

Furthermore, substantially all of the binders will enable cellulosederivative or varnish coatings and films tobe applied to the sheetwithout diiliculty.

In the case of artificial leather, I utilize coatings of pyroxylin,alkydresins and similar substances which will produce the desiredsurface,

and these, by reason of the flexible and resilient `character of mylaminated base, will be prevented from cracking or scarring in use.

In the manufacture of floor coverings, such as linoleum and artificiallinoleum, I employ the varnishes and lacquers above mentioned, withequal success since the elastic and flexible nature of the coatings willbe retained because of thelexibility and resilience of the laminatedbase.

I have set forth above the various components of the web, namely thebres, the cork and fibre mixture, the binders, and examples of coatingmaterials and finishes.

The method of carrying out the invention to produce the nal binderincorporated sheet will 00 now be described. I will have recourse to anyone of three steps, and in some cases will combine one or more of thesesteps in accordance with the type of sheet desired. K

In the drawing, I have illustrated in Figure 8 a saturat'ing treatment.'Ihat is to say, the web either formed on a single or multipleFourdrinier machine, or upon a cylinder type machine, is entrainedthrough the saturating bath as shown in Figure 8.

In this method. the density of the web will be controlled and moreoverits characterwill be determined by the nature and size of thev cork, thenature of the fibres, and the amount of "eating to which the mixture issubjected. vAlso the `75 structure of the web will be regulated by thepercentage of cori: to fibre or vice versa, and it will be understoodthat I may produce a web in which either of these componentspredominates.

Another step and one equally preferable to the saturating treatment forincorporating the binder, is by the beater addition. That is to say, thestock will have admixed with it in the beater a proper percentage of thebinder for the final article. Another process of incorporating thebinder into the web is by pre-mixing, wherein the binder is mixed withthe components of the stock before they are submitted to the beateraction.

By these methods not only may the structure o1` the web be controlled,as previously described, but also, in the case of the stratified sheet,the percentage of binder and the type of binder may be controlled in therespective layers of the web. In each case I am enabled to control thedensity oi' the web. the character of the components and their amount,i. e., their relative percentage with respect to each other and theamount and character of the binder or binders present in the individuallayers of the iinal web.

With respect to pre-mixing and beater addition, it will be understoodthat the components may be individually pre-mixed with the binder, or amixture of the components pre-mixed with the binder and the sameprocedure followed in the beater.

I may also add one or more of the components of the binder to the corkand/or bres before mixing or to the beater mass, and the furthertreatments may take place during the formation of or after the web isformed. In other words, I may resort to the single use of pre-mixing,beater addition, or subsequent bath saturation in order to impregnatethe web with the binder, or I may utilize a combination of any two orthree of the above processes. As an illustration, I may add a binder bypre-mixing and add more of the same binder or another or a modifyingagent in the beater or by subsequent immersion in the bath. In otherwords, independent consecutive treatments with the components of thesaturant may be resorted to according to the binder employed and thespecific qualities required in the resultant product. I

Immersion treatment` The web will be produced on the apparatus shown inFigure 7 or a multiple or single Fourdrinier. In the case of asingle-ply web of cork and fibers, its density will be controlled andthe speed of travel through the bath regulated y whereby the amount ofimpregnation, i. e., percentage of rubber-like or other binder present,will be accurately and uniformly maintained. If the web is dense, asmaller amount of binder will be absorbed. 'Ihe quantity of binderabsorbed will vary in inverse proportion to the density of the web andthe speed of travel of the web.

In the case of the laminated integral and composite web, i. e., built-upweb, the same conditions apply except that the layers will usually be ofdifferent density and therefore less binder will be present in the layeror layers of greater density than in the one or more of less density,subject, of course, to the limitation that I could not eiiciently in allcases introduce a high percentage of binder in the inside plies by thesaturating process, where the outside plies are very dense, since thesewould present some difilculty to the introduction of the binder throughthem into the more absorbent inner plies. Therefore, in a final productoi.'v this kind, I preferably resort to beater addition or pre-mixing inorder to introduce a high percentage of binder in the core and lowerpercentages in the outside plies.. As an alternative, oi' course, I willresort to pre-mixing or beater additionto introduce Athe binder into theplies of the core and introduce the binder in the-surface .layers by animmersion treatment. Specifically, and for purposes of illustration,since I have saturated webs of the various structures above set forth,(see (a) (b) (c) (d)) and have employed the various binders exemplified,the web will comprise a thin surface layer of iibres constituting apaper-like web and a layer of cork and fibre mixture. The thinpaper-like layers are of greater density than the cork and fibre layeror vice versa.

'I'he web will be fed either continuously from the paper making machineor from storage rolls of the untreated material as shown in the drawing.

In Figure 8 the tank contains, as the impregnating bath, normal latexcontaining to 30% 25 rubber, 2% colloidal sulphur (based upon rubberpresent), 1% to 2% (based upon the content) of a suitable lowtemperature accelerator such as piperidine pentamethylenediathiocarbamate, 2% (based upon the rubber content) of a suitableactivator such as colloidal zinc oxide, and 2% (based upon rubberpresent) of Neozone L (du Pont). 'Ihe sheetl saturated with thissolution may be dried at 135 F. and heated 'to about 160 F., to cure therubber. This solution produces a very flexible product. The iinal sheetmay have a rubber content up to substantially 65% ofthe iinishedproduct. To increase the rigidity of the product I may resort to the useof larger percentages of colloidal sulphur and longer times of curing.The respective proportions indicated'may be departed from as desired andare simply given by way of illustration.

Also by way of illustration I will treat similarly a single ply web ofcork and bers as herein de- 4.; scribed, the density of which has beensuitably controlled. 'I'he webs so treated are dried in any suitablemanner, as on the 'drying rack or rolls as shown. I'he web is thereuponwound up into 5U commercially distributable rolls. The iinal productsare excellent for sealing materials and gaslets, being substantiallyresistant to water and weak acids and alkalis.

The web treated by immersion, as just described, has permanently andinsolubly incorporated throughout its cellular structure, the flexibleor rubber-like binder. 'I'his complete saturation is attained by reasonof the interstitial nature 'of the web. That is to say, the presence ofthe separator, i. e., the cork particles, and their interlaced relationwith the fibres, produces cells. air spaces and voids, whereby the webexerts a maximum capillary eilect and the iibres are impregnated and thecorkparticles coated.

In fact, both the fibres and cork are encased in the binder, and thethorough permeation of the web assures the presence uniformly throughoutthe web structure of suiiicient binder to obtain and preserve thequalities of strength, resilience and flexibility or stiffness.

In this connection, a single bath may be employed or several independentimmersions resorted to. Thus, in a laminated structure I may incorporatethe glue and glycerine in one bath and paraformaldehyde in another, orplace all in a single bath, with a suitable retardant, i. e., oxallcacid, to delay the glue formaldehyde reaction, to saturate the outsideplies after a resinous or rubber binder has been incorporated bypremixing or beater addition in the inside plies.

Further, the resinous and latex binders are capable of being cured inthe sheet by means of heat and pressure or heat alone without producingany deleterious results. This is particularly true with bakelite resinsas well as the rubber saturants, and I have described above specificbaths composed of these two materials. In some cases suitable dryers maybe added to the varnishes or resins respectively, in order to decreasethe temperature and time of curing.

Therefore, without describing them in detail, I refer to Figure 8wherein the single ply or mul' I tiple ply web is passed through asingle bath of a rubber or resin saturant and then through a curing anddrying chamber over racks or rolls to vulcanize or cure the binder. Thetemperature of the chamber and the temperature and/or pressure of therolls will be regulated in accordance with the particular saturantsolution or mixture employed, according to its determined amount in thesheet and the setting or hardening required.

By way of illustration, since I use any of the structures mentionedabove (see (a) (b) (c) ((1)) and the binders exemplified in theimpregnating method, the cylinder forming the top ply of paper is fedwith a mixture of cork and nbre which has been subjected to a severebeating in order to decrease the porosity and subsequent absorption ofthis part of the web. The paper web A is` formed and dried in the usualmanner and then passed through a bath containing a solution oi asuitable rubber-like composition as described above to saturate the weband then passed to a suitable drying arrangement as shown to evaporatethe solvent and cure, i. e., vulcanize the rubber.

In the case of the stratified web having a' layer or layers I5exclusively of fibres, i. e., a paperlike web, this thorough and uniformpermeation is obtained, since such layers are porous in accordance withtheir density, permitting capillary action and the fibres are absorbentand capable of impregnation.

Any of the above mentioned binders may be used, as determined by theproduct desired, and prepared as a bath with their modifying agents,through which the sheet is passed.

With respect to saturation with a bath of a rubber or resinouscomposition as herein described the respective plies of the sheet willbe controlled as to density. i. e., absorbency. As for instance, a moreabsorbent furnish may be supplied to the vats feeding the cylinders toform the surface ply or plies. The resulting web when subjected to therubber or resin impregnating bath will absorb a high percentage ofrubber in the surface layer or layers than in the intermediate orconcealed layers, thus furnishing resistance to Wear at the point ofcontact when the product is in use.

In other words, the density of the outer layers would be so low, so asto permit the introduction of a high percentage of rubber in thesurface. The density of the inner or intermediate plies could beincreased so that less rubber would be located in the center sectionwhere it is not needed.l y

'I'hus by controlling the density of the outer layers, I increase therate of absorption during the, saturating process, so as to get a highpercentage of rubber on the surface.

For wear resistant material. as iloor coverings, I select a resin orrubber saturant as above mentioned. yThese can be cured in the sheet togive a hard finish. and a sheet which will be abrasion resistant andresistant to the action of water. mineral oils, as well as organic andinorganic solvents. The amount present will be determined by the densityof the web and the method of binder incorporation employed. Thus whenwear resistant material is desired, it can be made by putting a highpercentage of the selected binder in the top surface which can beaccomplished l5 by making tliesurace ply very absorbent if sat urationis to be resorted to or by putting in a high percentage of binder in thetop ply during the paper-making process by beater addition or premixing.In other Words,l I rely on density control to get the high percentage ofbinder on the top ply when saturation is employed whereas I preferablyput the binder in during the papermaking process by pre-mixing or beateraddition in most other instances to accomplish the 254 result. As aboveexplained, I also resort to a combination of 'both methods.

Heater addition A preferred method oi incorporating a rubberlike binderin the webs which have been described is by beater addition wherein lthebinder is incorporated with the nbre or cori; and fibre mixture as aunal step in the beater process before the stock passes on its way tothe vats. A typical example ci this process is as follows:

The well-beaten and well-purified (especially from calcium salts) fibresor bres and cork, made ready ior the addition of latex, are treated per1200# fibre or libre and corn mixture, with 7 lbs. of4 dissolved nahecaustic soda to insure definite alkalinity for complete dispersion ofthe latex before coagulation. I insure a pH of 11.0 or over at thisstage. Next, 6 lbs. of hemoglobin dissolved in a V4 bbl. of water isadded as a protective cclloid, for which purpose the addition of thesilicate and casein, ywhich are later added, 'is used. At this stage, Imake sure of the precipi=Il tation, as insoluble salts, of any residualcalciuin, by theaddition of 5 lbs. of dry oxalic acid 5o and 1%, gallonsof ammonia water.

Next, 29 lbs. of commercial (A or U grades) vof silicate of soda areadded, after which 3 lbs. of ,casein dissolved in ammonia water areadded tov the beater. t

i After mixing the above ingredients, a sufiicient quantity ol latexsolution is quickly added to the circulating stock in the, beater togive the desired amount of rubber in the finished sheet. Before theaddition of the latex, the beater roll is raised to reduce danger ofpoor laten coagula tion. As soon as the latex emulsion is furnished,sumeient 8% I solution of paper-makers alum, that is, aluminum sulphate,is added to coagulate tbe latex, which coagulation is evidenced by thec5 clarification of the water surrounding the libres. An average of 160lbs. dry alum per beater isV necessary to coagulatel8% of dry rubber.Higher percentages of rubber will require more alum.

At this stage, the circulation of the stock in the beater is stopped andthe stock is allowed to stand for i'lve minutes. At the end of thistime. circulation is again started when about lbs. of alum in a 15%solution isvadded to the beater to make the mixture strongly acid. Whenabout 75 one-half of this quantity of alum has been furnished to thebeater, the valve in the latter is removed and the stock is at onceemptied into the chest on its way to the machine.

.Also in lieu of using dierent or equal per centases oi' the same binderin the stock in various vats feeding the cylinders on a cylindermachine, we may use entirely diderent binders in the respective stockssupplied to the separate vate, since it is possible to prepare the stockfor each vat by a separate pre-mixing and beater operation. As anexample of this method of operation, a top or surface ply of papercontaining rubber may be formed in the same manner given above for thetop surface ply oi the first previous example having a rubber-likebinder. The other plies of paper may be made oi a furnish prepared bypre-mixing and consisting of 40 parts by weight of petroleum baseasphalt, iiow point approximately F., 30 parts by weight of 3o mesh corkand 30 parts by weight of suitable rag fibre. The resulting mix orfurnish. after proper dilution is then beaten for one-half hour in anordinary beater and the respective stocks diluted and fed to the vatsinthe usual way.

En the manufacture of door coveringsand the like, a low percentage ofthe binder may be placed in the cork fibre mixture used to feed the vatsforming the center and, in some cases, the bottom layers, while a highpercentage of a hard finishing binder may be placed in the stock fed tothe vats forming the surface layer so as to offer a sudlcient resistanceto Wear. Also, where a high percentage of the hard bind= er is used inall the plies, then the material will be relatively stid. Thus equal ordiderent percentages of the same binder or a diderent one may beincorporated in the separate plies by the beater addition process.

It will be observed that by the beater addition process I am able tohave a relatively thin paper-like layer provided with a relatively smallpercentage of one of the binders above referred to, and oi high or lowdensity, and a layer of cork and fibre mixture of greater or lessdensity than the paper-like layer and containing a greater or lesspercentage of the binder. Furthermore, I will incorporate any of theseveral binders above referred to, and in addition the concentration ofthe binder, that is, its adhesive eilect, may be diderent from therespective layers.

Also, l Will use for some of the layers a binder capable of giving ahard nish, and l may incorporate in the respective layers diderentbinders selected from those listed above, whereby when the sheet issubjected to a curing action, one thereof will become hard and Wearresist ant while the other will become resilient.

By the beater addition process I am enabled to produce flexiblematerials, absorbent materials, materials having a hard nish andabrasion resistant and also am able to produce a relatively stillproduct.

Pre-mixing With respect to pre-mixing, the same control is available asjust described in connection with beater addition. The step ofpre-mixing, however, comprehends adding the rubber-like binder to thepaper-making components before they are submitted to the beaters.

By pre-mixing, the binder may be mixed with the components oi the webindividually, as a mixture, or both.

'I'he invention contemplates the introduction of different or equalpercentages of the same orl different binders into the respective pliesof the web, by a combination of the pre-mix and beater additionprocesses. 'Ihe following is a specic illustration of the method ofcarrying out this DIOCGSSI v Y For the surface layer or No. 1 furnish,50 parts by weight of rope fibre is saturated with an equal amount ofwater and placed in a steam jacketed mixer, together with 60 parts byweight of phenolic resin having a flow point of 70 C. to 80 C., and 50parts by weight of cork, 30 to 150 mesh. The entire mass is thenmixed ata temperature of 90 C. for forty-ve minutes. Hot water, 50 parts byweight, is added and the mixing continued for fifteen minutes, whencethe entire mass is removed and placed in a suitable beater. 'I'heconcentration in the beater is so adjusted as to give the proper beatingconsistency, that is, approximately 5%. solids, and beaten for one-halfhour. The resulting furnish is then suitably diluted and u'sed to feedthe cylinder forming the surface ply in the final paper-like material.

A No. 2 furnish for the bottom or intermediate layers will be preparedby incorporating a rubber-like binder by beater addition after themethod previously described. Thus, the final product may be made tocontain a surface layer or layers of resinous material while theremaining layers will be permeated with a rubber-like binder. It will beseen that various modifications and combinations are readily available.

The surface and bottom plies may be the same;

i. e., rubber or resin furnish, and the intermediate plies resin orrubber furnish.

The furnishes suitably diluted are fed to the cylinders in accordancewith the desired sheet,

surface'ply and intermediate and bottom plies. The cylinders so fed, asdescribed above, are operated to give a paper-like product with asurface layer or layers containing a high percentage of resin or rubberand other plies containing less binder or vice versa. The resultingpaper is dried and cured in order to set up the binder. K

Likewise, the curing treatments will be sub-A stantially the same, thatis, the web will be formed from the respective stocks and thereafterpresented to the curing chamber over racks or rolls and at appropriatetemperatures` and pressures or both, to obtain the desired setting ofthe binder.

By resorting to pre-mixing and/or preferably beater addition, a productdesirable for insoles can be formed, which has high resistance to teardue to a high percentage of rubber or other binder in the inner layersbut which has absorbent surface layers due to the decreased percentageof resin and/or rubber added to the beaters supplying the vats whichmake up these particular plies. Where heretofore it has been customaryto produce a laminated article of this type by forming the layersindividually and by bonding them by a rubber or other cement, the effecthas been that the cement between the respective preformed layers acts asa seal between the respective layers and prevents moisture from passingfrom one side to the other, which is corrected by the present processand article. For example, on the paper making machine I would produce bybeat-er addition or pre-mixing, a lami- 75 nated sheet having a smallpercentage of rubber that is, 'to appropriate cylinders for forming theon the top layerwhich vwould insure th'- insole absorbency as required.I couldl not 'efficiently introduce a high percentage of rubber in the'inside plies by the saturating process. because where the outside plieswere very dense they would present some dimculty to the introduction ofthe binder f through them to the more absorbent inne'rfplies. Therefore,if the final product-is to have absorbent outside plies and stillcontainv the binders, I preferably resort to beater addition and makethe completed product on the paper-making machine', so that its outsidelayers will contain less binder and therefore be more absorbent as toperspiration when used as inner soles, for example.

As modifications of the three methods which are embodied in thepaper-making process, Imay subject the respective stocks or any one ofthem to a pre-mixing or beater addition treatment and thereafter to asaturating treatment using dierent types of the binders hereinmentioned.

lSumming up the control features of the invention and regardless of thecomponents, the control of the qualities of the finished sheets aresecured by-flrst, the regulation of the density of the individuallayers, second, by the control of the percentagev and type of binderpresent in the layers, and third, by the combination of these twocontrol features. The density of a layer of paper composed of plainfibre or of cork and fibre or any other components from ywhich the paperwill be made, can be varied in the paper-making process (without theintroduction of a binder of any kind) by varying the time of beating,length of fibre, size of cork particles and relative proportions ofthese or other components employed. A multiple ply paper made on acylinder paper-making machine can therefore be made by laminatingseveral plies of paper' having a different density in each ply. Whenthis completed sheet is saturated, the amount of satu-l rant which thevarious plies will absorb will be different, depending upon the varyingrates of absorption resulting' from the variation in density from ply toply, subject to the practical limitations heretofore disclosed. That is,for example, a large amount of binder cannot be introduced into a porouscenter ply if the outside plies are of greater density. Therefore, ameans of conJ trolling the amount' of binder or saturant present in thedifferent plies is presented by the density control of the individualplies, although as in the illustration just given, no binder isintroduced into the plies'during the paper-making process.

Where pre-mixing and/or beater addition are resorted to, I not only varythe amount of binder present in the individual plies but vary as wellthe type of binder or binders in the individual layers. For example, Iuse different amounts of the same binder in vats II-lil and can usedifferent percentages of an entirely different binder in vats i0-I2. Thebinder is incorporated in the paper-making process either by pre-mixingor beater addition or both.

As a third variation,.I can have a combination of the cases justoutlined above whereby I control the density of one or more plies ofpaper (unimpregnated) and combine these plies on the paper-makingmachine with other plies containing controlled amounts of binder orbinders, adding by pre-mixing or beater addition or both. This productis then passed from the paper-making machine and saturated, in whichprocess the controlled densities of the plies which were not impregnatedwith a binder in the paper-making process, will control the iinal amountof saturant absorbed by these plies during the saturating process.

In other words, we have three definite m of controli 1. That, presentedas in the bath treatment, by regulating the amount of binder absorbeddue to varying the densities oi' the paper plies during the paper makingprocess.

2. By varying the percentages or lanioui'its of binders and the type ortypes of binders present in the individual plies or layers when suchbinder or binders are added by the pre-mixing and/or beater additionprocesses, and

'3. By the combination ci these two methods.

It will be understood that the coating treatment will preferably takeplace after the binder incorporated web has been formed and the coatingmay beapplied by immersion, brushing, spreadlng' or spraying. f

With each of the several methods I am enabled to obtain a exibleproduct, and 'by varying the type and percentage of binder and thecuring.. treatment, one which will have relatively greater stiffness.

It will be seen that by the control oi the density of the stock, thenature of the cork particles and bres and the beating action, as weilIas the percentage relationship of the components there i0 is producedthe structures herein described. In other words, I obtain a uniformproduct having the requisite amount of binder distributed throughout theinterstitial structure in exactly the amount required to form the nlshedsheet.

'With each process above outlined, the paper or boardas formed is passedthrough a heated chamber over a drying rack or preferably rolls as shownin the drawing to remove the solvent or solvents. In cases where a heatconvertible binder is present, the heat treatment is continuedsumciently to set the binder. In practically all cases a temperature offrom 80 to ido" C. 'was found preferable, the time, oi course, varyingwith the particular material.

Suitable coloring agents, for example, dyes or suspended pigments, maybe added tothe bind.- ers in order to obtain any desired color eiects.

In connection with the examples given, other dbres will be used, as forexample, rope, jute, wood, kraft, sulphite, hemp, alpha cellulose, rag,and the like; the proportion oi nbre can be varied as desired.

Although 50 mesh cork was speciiied in the above examples, this can bevaried over wide limits, and We have successfully used mesh ranges fromto 200.

In order to obtain different exibilltles, other rubber compounds thanthe examples given above can be used. Again, in the case of the rubbertlike or phenolic binder, this can be varied over wide limits, as forexample, from 20 to 80 per cent of the finished product.

By adjusting the proportions of binder with any of the methodsdescribed, a material suitf able for use in the plastic field can beprepared. 'Howeven in this case, the material is not given any severeheat treatment, care being taken that the paper is simply dried, inorder that a subsequent molding operation can be carried out (165 C.,1,000 lbs. pressure per square inch) .Y

The rubber-like binder compositions per se with their modifying agentsmentioned herein are all commercial products and I have set them forthas illustrative instances of binders which I have 75 utilized withsuccess and which are capable of permitting curing and setting oi thebinder in the sheet. The same is true with the coating materials.

Another very acceptable product which I make in accordance with thisinvention is va new gasket material and I use any or a combination otthe steps of binder incorporation explained above. Thus I will prepare aweb composed exclusively of asbestos fibres having relatively dense andimpervious surface layers and intermediate layers of less density andgreater compressibility. This structure may be reversed and the gasketprovided with a core of dense, impervious layers and surface layers ofgreater compressibility and less density and impermeability. Therelatively dense layers will be relatively thin with respect to the morecompressible layers although they may be equal to or oi greaterthickness, or the more compressible layers of less thickness than therelatively denser layers.

A single binder may be used or several dierent distinct ones for therespective laminae, and selected from those above mentioned, preferablyin accordance with physical and chemical ccnditions surrounding theparticular gasket application.

The gasket materiali may have any desired surface coating, as forexample a layer of graphite as well known in the gasket art.

A similar structure, i. e., one having a relativeiy dense,incompressible and impervious layer or layers and a layer or layers ofless density, greater compressibility and less imperviousness, is formedexclusively from any oi' the bres herein listed, asbestos being given asa further concrete example, and likewise the exact structure can beformed exclusively from mixtures oi cork and fibres. Again the structureis formed from layers composedV oi asbestos fibres mixed with one ormore of the other iibiz'esl mentioned, as rope fibre, or mixedwithcommiuuted cork, or comminuted cork and rope bre or one or more of saidother described bres. Furthermore, the structure is formed with layersrespectively exclusively oi asbestos bres and (l) layers exclusively ofone or more of the other fibres men tioned or of corkl and libres and(2l oi the asbestos mixtures just described.

As one concrete example the surface layers may be ci asbestos and thecompressible intermediate layers oi cork and bre mixture.

In each case the product will have a suitable binder incorporatedtherein, if required, a surface coating where desired, and/or a layer oigraphite or similar materiai.

In some instances, as where the surface layer is not required to besmooth, calendering may be omitted, and in other instances the thinpaperlilre web or the thin surface layer of cori: and

iibre will not require any calendering. However, for certain decorativepurposes Where a very high nish is required, I resort to calendering.

Referring to Figures 5 and 6, the sheets in accordance with thisinvention are combined with a preformed material itfsuch as a layer ofcloth, paper, 'synthetic resin, vulcanized nbre or rubber. Such layerswill be flexible or relatively stiff, as desired, serving as areinforcement for the web and may be permeable or impervious. Thepreformed material will be (see Figure 5) (l) a backing, (2) a facing,and (3) both, orisee Figure 6) a core. As to the core structure, thisalso may have a facing or backing, or both, oi the preformed material.

That is to say, the sheets will be constructed dit in accordance witheither of the webs of Figures 1 to 4. The combining may take place onany suitable combining machine, as for example, between opposed rolls.

5 A preformed facing and backing material may be applied. as thepermeated webs issue from the paper making machine or bath, and thecombining takes place simultaneously with the curing of binder and thedrying of the web, i. e., the combining rolls will be suitably heated.

'I'he adhesive may be applied to the surface of the preformed materialor the surface of the web. Pressure or heat sensitive adhesives areemployed as well as glues and binders of the type recited l5 above. Incertain cases the web will have excess binder present on its surface sothat additional adhesive will not be required. Again the web andpreformed nonpermeated material will be combined and then the compositesheet saturated in a bath of the binders herein described. Also thepermeated or non-permeated webs may be formed and wound into rolls, andthereafter combined with preformed material as required, or thecombining will be a continuous or consecutive step after or beforedrying of the web. Also, the combining may be accomplished with pre-cutsheets as with the manufacture of veneers.

These faced and backed products have a variety of uses and particularlyare useful for printing press blankets, insoles and rug anchors, as wellas floor coverings. 'I'hey may be suitably coated for any desiredpurpose with lacquers or varnishes as herein described.

For press blankets I may use any of the per- 35 meated webs hereindescribed, but I prefer to use for printing press blanket material asingle ory double ply web of cork and fibre in accordance with thisinvention. I saturate the web with a rubber-like binder or other binder,as for example a glutinous adhesive, i. e., glue and glycerine and setthe glue with formaldehyde. This will give a flexible blanket ofrequired strength and resilience. V

I will in some cases, where added strength is needed, apply a exiblebacking of paper, cloth or vulcanized ilbre. Also I apply the backing toboth surfaces of the web as shown in Figure 5 as a furtherreinforcement.

While I have indicated rubber and glutinous 50 adhesives, I also findthe resin binders satisfactory for press blankets.

As a modification, a non-permeated web of cork and fibre has one or bothsurfaces united to a backing as above described.

As a further modification a core of the backing material will beemployed such as cloth or paper and the webs united to opposite sidesthereof. A backing and/or facing will also be used in some cases.

As a further form of printers blanket or make ready, and particularlywith reference to the use of vulcanized ilbre, I will employ arelatively thin sheet of this material, and adhesively unite 55 it toone of the sheeted products of this application, or to a layer wholly ofcomminuted cork particles and a binder, preferably one of those hereinmentioned. 'I'his material (i. e., cork and binder) may be sheeted ormay be spread upon 70 the vulcanized fibre sheet.

The outside surfaces of the blanket material will be treated in suchmanner as to be smooth and impervious and non-adhesive to printing ink.

For insole material I will use any of the various 75 webs hereindescribed and any of the several binders to obtain a flexible, strongand absorbent material which likewise is resilient.

Preferably the exposed portion or tread surface will be freely absorbentto perspiration and hence will have only a minimum of binder present.

A' premeable facing or backing such as muslin or other open web fabricwill sometimes be applied to one or both surfaces of the web as areinforcement.

'I'he undersurface will also in some cases carry a pressure sensitive orheat sensitive adhesive of which many varieties are commerciallyavailable.

The insoles will be stamped out of the sheet in the usual manner.

As one illustration, I will, by pre-mixing or beater addition, put asmall percentage of binder such as rubber latex in the top plies (fibrealone or cork and fibre) in order to produce absorbency of the finishedinsole on account of perspiration. In the intermediate and bottom plies,I introduce a high percentage of a binder such as a resin and/or rubberlatex in order to increase the strength of the product, its resistanceto wear and ability to stand sewing.

Other of the binders are equally applicable.

A new and important use for treated cork fibre v(single ply ormulti-ply) resides in its application as Ia rug anchor. Tests with asheet of cork bre impregnated with a rubber-like binder as well as withglue, glycerine and formalhehyde under small rugs on polished floorswere very satisfactory. The rug does not slip on the cork fibre surfaceand the cork fibre grips the polished floor so that there is no movementof the rug relative to the cork bre or the cork ilbre relative to theoor, or both the cork fibre and the rug relative to the floor.

Cork bre treated with the various binders mentioned produces a veryacceptable rug anchor with or without the addition of a reinforcingmaterial such as a layer of paper or cloth. This expedient is used insome cases in order to prolong the life of the anchor because small rugsare constantly being removed from the floor for cleaning purposes, andin the handling, a thin sheet of cork fibre might ultimately becometorn. I use a combination of cork nbre and cloth, and cement the clothon the side of the cork fibre which is in contact with the bottom sideof the rug. I also put two layers of cork flbre on either side of a coreof reinforcing cloth. Instead of impregnating with a rubber-like binder,I also use a resinous binder.

The products of this invention, especially treated cork and fibre, areadapted for 'use as anti-squeak material on automobiles. In thisapplication, the compressibility and resilience of the product insure atight joint between the adjacent surfaces and at the same time due tosound absorbency prevent noise and squeaking. It is readily processedinto the desired form, that is, cut, slit, or folded. It is alsosubstantially weatherproof and does not disintegrate when wet.

Another automotive application is the use of window channel material.The compressibility and resilience of the cork and fibre products makepossible a tight joint with glass and at the same time afford a yieldingor cushioning support to prevent window breakage. Other desirableattributes for this purpose are availability in various colors,weatherproofness, resistance to disintegration when wet, soundabsorbency and ease of processing. i

It will be understood that the various structures set forth herein willbe permeated with various of the binders, for example, the surface layerwill be permeated with a glutinous binder, i. e., glue, glycerine andformaldehyde, and the intermediate plies and bottom plies with aresinous material or a rubber-like material. Thus also one layer willcontain a rubber-like binder and another layer a resinous binder.Similarly other sheets will be formed in which either the resinousbinder or the rubber-like binder will permeate the surface layers andthe other binders the intermediate and bottom layers. In some cases thetop and bottom layers will be permeated with the same binder.

In referring herein to a resinous binder. I mean various natural andsynthetic resins and compositions thereof which are well-knowncommercial articles, and in connection with rubberlike materials, I meanlatex and similar latices, i. e., balata and gutta-percha and variousrubber compositions, all of which are available in the trade.

The term "paper-like is intended to cover the webs produced inaccordance with this invention on a paper-making machine.

I claim:-

1. 'I'he process oi' making sheet material comprising a laminated webhaving paper-like layers felted to produce an integral compositestructure which comprises preparing separate stocks of differentdensities, each of a. mixture of separator and fibres, felting thestocks on a paper making machine into an integral web, the laminae ofwhich have different coeiiicients of absorbency and saturating the webwith a rubber-like binder to include such binder in the web inaccordance with the absorbency of the layers thereof.

Z. The process of making sheet material com- 40 prising a laminated webhaving paper-like layers felted to produce an integral compositestructure which comprises preparing separate stocks of differentdensities, each of a mixture of comminuted cork and ilbres, felting thestocks on a 45 paper making machine into an integral web, the

laminae of which have different coeilicients of absorbency andsaturating the web with a rubber-like binder to include such binder inthe web in accordance with the absorbency of the layers thereof.

3. The process of making sheet material comprising a laminated webhaving paper-like layers felted to produce an integral compositestructure which comprises preparing separate stocks for the individuallayers, incorporating in some of said stocks predetermined percentagesof a rubber-like binder material, felting the stocks into a laminatedweb and saturating the web to incorporate a binder material in other ofthe layers of the web.

4. Sheet material comprising a laminated paper-like web having thelaminae thereof felted together into a substantially integral structure,rubber-like binder material in the laminae of said web, one of saidlaminae having a greater percentage of binder than another thereof andthe binders being of respectively different types whereby to providelaminae of diierent characteristics.

5. Sheet material comprising a laminated paper-like web having thelaminae thereof felted together into a substantially integral structure,rubber-like binder material in the laminae of said web, the said laminaehaving equal percentages of respectivelyr different types of binderswhereby to provide laminae of different characteristics.

6. Integrally laminated sheet material of paper-like form having one ofits layers permeated with a rubber-like binder and another with aglutinous adhesive.

7. Integrally laminated sheet material of paper-like form having one ofits layers permeated with a rubber-like binder and another with abituminous binder.

8. Integrally laminated sheet material of paper-like forrn having one ofits layers permeated with a rubber-like binder and another with aglutinous adhesive and another with a bituminous binder.

ELMER C. SCHACHT.

